| The experiment was designed to study the influence of weaning age and different protein of milk replacer on performance,nutrient digestibility,organ development and scrum biochemical index of goats.So as to provide theoretical basis on the mode of the ablactation for lambs in Chongqing,promote the black goat rearing in the country.Different protein of Milk replacer and the concentrate supplement of 45 days old were in accordance with the demand of rearing goats and the reports of related literatures.The experiment used two factors trial design.The experiment,was divided into five trial groups, the group of feeding milk protein weaned at 15-day-old,the group of feeding vegetable protein weaned at 15-day-old,the group of feeding milk protein weaned at 30-day-old,the group of feeding vegetable protein weaned at 30-day-old,the group of natural weaning was control group,with 6 goats per group and 3 ewes and 3 rams per group.Feed the milk replacer of different protein,after 15 days,the performance,nutrient digestibility,scrum biochemical,compensation capacity of growth in the late periods and the weight in the 8th month were investigated.Two rams were slaughtered at 45 days old to study the effect of two differents milk replacer on the weight of stomachs and the shape of intestinal villi.All groups feed weaning feed after 45 days old,and digestibility of weaned feed were investigated.The results showed;(1) when lambs were weaned at 15 days old,milk protein group and vegetable protein group had impact on performance in different days.At 30 days old,the weight of milk protein group and vegetable protein group were lower than control group significantly(P＜0.05).At 45 days old,the weight and average daily gain of 15-day-old weaned group were lower than control group and 30-day-old weaned group(P＜0.05).At 240 days old,the weight and average daily gain of 15-day-old weaned group were extremely significantly lower than control group and the 30-day-old weaned group(P＜0.01),and tend to diarrhea and death usually.The performance of 30-day-old weaned group were nearly to control group,compensation capacity of growth in late period was significant and was not easy to diarrhea and death.The weight and average daily gain of group of milk protein at 30 and 45 days old were better than protein group significantly(P＞0.05).(2) With weaned days being increased,the digestibility of dry matter,calcium,phosphorus and ether extract was increased(P＞0.05).The apparent digestible energy of milk protein of 15-day-old weaned group and 30-day-old weaned group were increased significantly compared with the vegetable protein of 15-day-old weaned group(P＜0.05).When weaned ages at 15 days old,the digestibility of crude protein of milk protein group was increased extremely significantly compared with milk replacer of vegetable protein group(P＜0.01);When weaned ages at 30 days old,the digestibility of crude protein of milk protein group and vegetable protein group had no significant effect(P＞0.05).With weaning days being increased,the digestibility of lamb on weaned feed was increased,at the same weaned days,the digestibility of dry matter,crude protein,apparent digestible energy,calcium,phosphorus and ether extract of milk protein group was better than vegetable protein group(P＞0.05).The digestibility of dry matter of 15-day-old weaned group was significant lower than 30-day-old weaned group(P＜0.05).The digestibility of crude protein of 15-day-old weaned group was decreased significantly compared with 30-day-old weaned group and control group(P＜0.05).The apparent digestible energy of milk protein of 15-day-old weaned group was decreased significantly compared with 30-day-old weaned group and control group(P＜0.05),the apparent digestible energy of vegetable protein of 15-day-old weaned group was decreased significantly compared with vegetable protein of 30-day-old weaned group(P＜0.05),and was decreased extremely significant compared with control group(P＜0.01).(3) The development of rumen,reticulum,omasum and abomasum were improved when weaned ages at 30 days old,the weight of the four stomach were 30-day-old weaned group＞control group＞15-day-old weaned group.At the same weaned ages,the weight of rumen,reticulum, omasum and abomasum of milk protein group were higher than vegetable protein group,but there were no significant effect between the two groups(P＞0.05).The weight of rumen of milk protein of 30-day-old weaned group was improved significantly compared with control group and milk protein of 30-day-old weaned group(P＜0.05).The weight of rumen of control group was higher than vegetable protein of 15-day-old weaned group,but less than 30-day-old weaned group.The weight of rumen of 15-day-old weaned group were decreased significantly compared with 30-day-old weaned group and control group(P＜0.05).(4) With weaning days being increased,the content of blood glucose and blood urea nitrogen was decreased,the content of blood cholesterol was increased.When weaned at 15 days old,the content of blood glucose of control group was decreased significantly compared with milk protein group and vegetable protein group(P＜0.05),but there was no significant effect between the two groups(P＞0.05);The content of blood urea nitrogen was vegetable protein group＞milk protein group＞control group,and there was significant effect between the three groups(P＜0.05);The content of blood cholesterol of vegetable protein group was decreased significantly compared with control group(P＜0.05).When weaned at 30 days old,the content of blood cholesterol of control group was decreased significantly compared with milk protein group and vegetable protein group(P＜0.05),but there was no significant effect between the two groups(P＞0.05);The content of blood glucose of vegetable protein group was decreased significantly compared with control group(P＜0.05);The content of blood urea nitrogen of vegetable protein group was increased significantly compared with milk protein group and vegetable protein group(P＜0.05),but there was no significant effect between the two groups(P＞0.05).(5) Both 15-day-old weaned group and 30-day-old weaned group had damaged the height and shape of intestinal villi to a different extent,and did not restore to the level of breast-feeding until 45 days old.Feed milk replacer to 15-day-old weaned group,the height of intestinal villi was lower than control group,jejunal villi serious loss,duodenum and ileum had smaller difference.Feed milk replacer to 30-day-old weaned group,milk protein group and vegetable protein group had smaller difference compared with control group on intestinal villi.(6) When weaned at 15 days old,both milk protein group and vegetable protein group had impact on secreting of digestive enzymes to a different extent,in addition to the activity of protease was not significant in the duodenum,the activity of digestive enzymes in different paragraphs of small intestine was increased extremely significantly compared with control group(P＜0.01);The activity of digestive enzymes of milk protein group was higher than vegetable protein group,but there was no significant effect between groups(P＞0.05).When weaned at 30 days old,in addition to the activity of amylase was higher than control group,the activity of protease and lipase was lower than control group.In conclusion,lambs weaned at 30 days old,not like 15-day-old weaned group as the impact on performance,the development of digestive tract and the secretion of digestive enzymes,and can stimulate the development of digestive tract and the secretion of digestive enzymes earlier than 45-day-old weaned group.When lambs weaned at 30 days old,feed milk replacer of vegetable protein and milk protein have less impact on performance in earlier period,and have significant impact on compensatory growth in later period.So lambs can weaned at 30 days old,and can feed milk replacer of vegetable protein. |
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